Rotatable ultrasound transducer probes, such as transesophageal or TEE probes, are used for viewing planar ultrasound images of a patient's heart from inside of the patient's esophagus. The tip of the TEE probe houses a rotatable array element. Rotation of the array element causes a corresponding rotation of the image plane about an image axis. Once the TEE probe is inserted down the esophagus, rotation of the array element is controlled at a remote distance from the probe tip. TEE probes are described by Solomon et al. in U.S. Pat. No. 5,181,514 and Harui et al. in U.S. Pat. No. 4,543,960.
In contrast to TEE probes, in which rotation of the image plane is controlled at a remote distance from the probe tip, finger probes are attached to a physician's finger. The image plane orientation is then manually controlled by the movement of the physician's finger. Finger probes are well suited for internal imaging through the body cavities and in interoperative environments during open heart surgery or vascular surgery. One type of finger probe taught by Hanaoka et al. in U.S. Pat. No. 5,284,147 uses a stationary imaging element. While the image axis of the stationary imaging element may be readily aimed at the patient's body part to be viewed, rotation of the image plane about the image axis to obtain other critical views of the patient's body part is implemented by physically rotating the finger probe and its attached cable. Since the body cavities into which the finger probe is inserted, are often small and space constrained, physical rotation of the finger probe is limited, which reduces viewing access to the patient's body parts.